bacteria Cutibacterium acnes actually prolong the nematode's lifespan and help its innate immune system fight against the pathogen Staphylococcus aureus.


Date:
October 27, 2021
Source:
Osaka City University
Summary:
Researchers reveal correlation between ribotype (RT) strains
of Cutibacterium acnes, which are found in human skin, and the
lifespan of the nematode Caenorhabditis elegans. Strains RT4
and 8, which are associated with acne in human skin, shortened
the lifespan of the nematode, while RT6, which are predominantly
found in healthy human skin, did not. Also, it was found that the
healthy skin-related RT6 strain of C. acnes improved C. elegans
resistance to the pathogenic organism Staphylococcus aureus.



FULL STORY ========================================================================== Cutibacterium acnes, a bacteria that is known to cause acne, is also
widely spread on people with healthy skin. Recent advances in gene
sequencing have shown that differences in the genetic background between strains of bacteria may lead to differing roles in the skin. A new study,
done without animal (mammal) testing, shows that the nonpathogenic strain
of C. acnes improves the skin's resistance against the infection-causing bacteria Staphylococcus aureus.


==========================================================================
The report appears in Microbiology Spectrum of the American Society
for Microbiology.

"It is likely that C. acnes maintains skin health by inhibiting common pathogens like S. aureus from invading skin tissue," said lead author
Ayano Tsuru, a graduate student at the Graduate School of Human Life
Science, Osaka City University. "Instead of using mammals, we explored
this with Caenorhabditis elegans, a 1mm nematode that has basic animal
parts like a nervous system, muscles, and digestive tract, as well as
a body surface barrier equivalent to human skin." In this joint study
between the Osaka City University and Okayama University, researchers
used C. elegans to investigate the biological effects of several strains
of C. acnes isolated from human skin.

Results showed that ribotype (RT) 4 and 8 strains, a classification of
bacteria strains based on polymorphisms in rRNA, which are often detected
in the skin of individuals suffering from acne, shortened the lifespan
of the nematode, while RT6 strains that are often found in the skin of
people without acne, did not.

"This means that," explains supporting author Yumi Hamazaki also a
graduate student at the OCU Graduate School of Human Life Science,
"ribotype strains of C. acnes that cause acne in humans correlated
with virulence, or a shortening the C. elegans lifespan." The team
further clarified this finding by investigating the effect of healthy skin-associated strains of C. acnes on the nematode's susceptibility to S.

aureus. Results showed the survival period of nematodes infected with
the pathogen to be longer than the control group.

Also, RNA sequencing analysis of changes in the gene expression revealed
that strains of C. acnes behind healthy skin activated a group of
genes related to innate immunity and biological defense responses in
C. elegans. "Further analysis of nematode gene mutants" states Professor
Shuta Tomida of the Center for Comprehensive Genomic Medicine at Okayama University Hospital, "suggests this resistance to S. aureus was mediated
by TIR-1 and p38 MAPK pathways that are responsible for innate immunity
and not by suppressing the growth of the S.

aureus pathogen.

The implications of this study are wide and exciting.

By focusing on ribotypes related to the absence of acne, this study
revealed there are beneficial aspects of acne bacteria, which have had
a generally negative image.

As advisor to the study, Eriko Kage-Nakadai, professor at the OCU
Graduate School of Human Life Science puts it, "this reminds us that when evaluating the biological effects of certain bacteria, there is a need
for a discussion at the strain level. Also," the professor continues,
"the fact that we succeeded in detecting the effects of skin indigenous bacteria using C. elegans illustrates the usefulness of this nematode
as an alternative model in the field of epidemiology." Lastly, in the landscape of probiotic research currently dominated by bifidobacteria
and lactobacillus, the team is excited at the expectation that this
study may lead to the application of healthy skin-related strains of C.

acnes as a "non-drinking probiotic." ========================================================================== Story Source: Materials provided by Osaka_City_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Ayano Tsuru, Yumi Hamazaki, Shuta Tomida, Mohammad Shaokat Ali,
Tomomi
Komura, Yoshikazu Nishikawa, Eriko Kage-Nakadai. Nonpathogenic
Cutibacterium acnes Confers Host Resistance against Staphylococcus
aureus. Microbiology Spectrum, 2021; DOI: 10.1128/Spectrum.00562-21 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211027134954.htm

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